#include <iostream>
#include <list>
#include <algorithm>


int main()
{
  std::list<int> s1;
  s1.push_back(1);
  s1.push_back(2);
  s1.push_back(3);
  s1.push_back(4);

  std::list<int> s2;
  s2.push_back(3);
  s2.push_back(4);
  s2.push_back(5);
  s2.push_back(6);

  std::list<int> s3(10);
  std::list<int>::iterator it;

  std::list<int>::iterator s1b = s1.begin();
  std::list<int>::iterator s1e = s1.end();
  std::list<int>::iterator s2b = s2.begin();
  std::list<int>::iterator s2e = s2.end();

  it = std::set_difference(s1b, s1e, s2b, s2e, s3.begin());
}
